Power modules, LED modules, or thermoelectric modules have a structure in which a power semiconductor element, a LED element, and a thermoelectric element are joined on a circuit layer made of a conductive material.
For example, power semiconductor elements for high-power control, which are used to control wind-power generation, electric vehicles, hybrid vehicles, or the like, require a large amount of energy in operation, and thus a ceramic substrate (insulating layer) formed of silicon nitride (Si3N4) having excellent heat resistance and an excellent insulating properties is widely used as a substrate on which the power semiconductor element is mounted.
An insulating circuit board (substrate for power module) is provided in which a metal plate having excellent conductive properties is joined to one surface of a ceramic substrate (insulating layer) to form a circuit layer. A metal layer having excellent heat-radiating properties is integrally joined to the opposing surface.
For example, a power module shown in PTL 1 has a structure having: an insulating circuit board (substrate for power module) in which a circuit layer formed of an aluminum plate and a metal layer formed of an aluminum plate are respectively formed on one surface and the other surface of a ceramic substrate; and a semiconductor element which is joined on the circuit layer via a solder material.
In addition, a configuration is employed in which a heat sink is joined on the metal layer side of the insulating circuit board (substrate for power module), and the heat transferred from the semiconductor element to the insulating circuit board (substrate for power module) side is diffused to the outside via the heat sink.